Rotary pump and motor hydraulic transmission with automatic speed control means



July 17, 1951 a. A. KANE 2,561,023

ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION WITH AUTOMATIC SPEEDCONTROL MEANS Filed Aug. 5, 1940 INVENTOR MPG/.17 A. K/INE ATTORNEYPatented July 17, 1951 ROTARY PUMP AND TRANSMISSION WIT CONTROL MEANSMOTOR HYDRAULIC 1: AUTOMATIC srnan v Garold A. Kane, Minneapolis, Minn.,assignor to The Northern Pump Company,

Minneapolis,

Minn., a corporation of Minnesota I Application August 5, 1940, SerialNo. 351,;474 9 Claims. '(01. 60-53) I This invention relates to acontrol device for a hydraulic assembly or system adapted to drive amovable member through a hydraulic motor.

of stroke of said pump and a connection giving It is now a commonpractice to drive many movable members by means of hydraulic motors.

Among the desirable features oi' driving by a hydraulic motor is onethat the motor can be controlled with nicety so as to control themovements of thedriven member. While the present invention has manyapplications, one use thereof is in driving or rotating a gun turret ona warship. Such a turret has anexceedingly large mass. It must bequickly accelerated when moved and must be decelerated under accuratecontrol so as to be brought to a stop at the desired point. It must notoverrun and must not be stopped with a shock.

It is an object of this invention to provide a simple and eflicientcontrol means for an assembly comprising a variable stroke pump and ahydraulic motor by means of which said motor and the member driventhereby may be eflectively controlled so as to be accelerated anddecelerated as desired.

It is a further object of the invention to pro- .vide a control systemincluding a motor, a variable stroke pump, a valve for controlling saidpump, a hand control means and connections to said valve for controllingthe same from said hand control means, said motor and said pump.

It is another object of the invention to provide a control systemincluding a motor, a variable stroke pump, a valve for controllin saidpump, a manual control means, connections from said hand control meansand motor to said -valve and a connection from said pump to said valvefor moving said valve in non-direct ratio to the change of stroke ofsaid pump.

It is still another object of the invention to provide a hydrauliccontrol means including a hydraulic motor and a variable stroke pump forsupplying fluid thereto, a valve for controlling said pump, a handcontrol means connected to said valve through a difierential mechanismalso connected to said motor together with a control means for saidvalve operated from said pump.

It is rather more specifically an object of this invention to provide ahydraulic control system including a hydraulicmotor, a variable strokepump for driving the same, a valve for controlling said pump to vary thestroke thereof from neutral to full position, a hand control meansconnected to said valve through a differential mechanism also connectedto said motor, a member moved in direct ratio to the change non-linearmovement between said member.

These and other objects and advantages of the invention will be fullyset forth in the following description made in connection with theaccompanying drawing in which like reference characters refer to similarparts throughout the several views and in which:

The figure is a view partly in side elevation and partly in verticalsection illustrating the invention, said view bein somewhatdiagrammatic.

Referring to the drawing a pump 10 is shown, the same being of thevariable stroke type. While any pump of the variable stroke type may beused, in the embodiment of the invention illustrated a pump of the swashplate multiple cylinder type is illustrated. Such a pump usuallycomprises a tilting plate Illa and the oscillating or swash plate liibin which are flxed the ends of piston rods lllc shown as having ball andsocket connections with plate Mb. The piston rods Inc will be connectedto the pistons said valve and movable in cylindersin a cylinder barrelHid. A pump of the generaLtypeqeierred to is ilius-' trated in thepatent to" H. D. ,Williams and R. Janney, No. 1,062,071, May 20, 1913.The tilting plate Illa is movable about trunnions and one end of one ofthe trunnions is shown at Hie. Trunnion we therefore moves about itsaxis in direct ratio to the movement of the tilting plate Illa. Theplate lOa is movable from neutral position in which it occupies a planeparallel with the end of the cylinder barrel or perpendicular to theaxis of the cylinders to full stroke position when it occupies itsmaximum angle to said plane. The delivery of fluid from the pump is inproportion to the position of plate Ilia. Pump III has a driving shaftlflg to which will be connected some suitable driving means such as anelectric motor. Inthe ,embodiment of the invention illustrated plate I0a has a projecting arm if to which is pivotally connected one end of ashort link II which is pivotally connected at its other end to a pistonl2. Piston i2 is shown as having a reduced and flattened central portionbetween the cylindrical end portions thereof for accommodating arm In!and link ll. Piston I2 is movable in a cylinder I3 having ports at bothof its ends and conduits I4 and I5 are respectively connected to saidends and communicate with said ports. Conduits l4 and ii are connectedat their other ends to a cylinder l6 having spaced ports 3 therein withwhich conduits H and I5 communicate. A piston valve H is fitted in andmovable in cylinder l5 and has end lands Na and Ho and a central landHe. Liquid controlled by piston valve H for moving piston |2 is suppliedthrough a conduit l5 connected to an auxiliary pump l9. Pump l9 willhave a relief valve portion |9a from which a conduit leads to the mainexhaust conduit 2| connected to the supply or storage tank 22. CylinderI5 is provided with discharge or exhaust ports adjacent each end withwhich communicate the discharge pipes and 25 which will extend to asuitable storage tank. Piston valve I1 is pivotally connected at one endto a link 25 which is in turn pivotally connected at its other end to alever 21. A coiled compression spring 25 is disposed between the lowerapertured end of cylinder l5 and the lower end of land Nb of valve ll,said spring being received in a counterbore in the end-of said land.Lever 21 at one end carries a stud 25 on which will be mounted a camroller adapted to be disposed in the cam groove 25a of a cam 25. ,Cam 29is mounted on a shaft 55 suitably iournaled in pump It. A pinion 5| issecured to shaft 55 and meshes with a gear segment 52 which is fixedlymounted on shaft or trunnion He. The other end of lever 21 is pivotallyconnected bypivot 55 to a head or member 55 mounted on the upper end ofa screw 55, said member being held on said screw by washer 51 and nut55. The screw 55 forms part of a differential mechanism and whilevarious types of differential mechanisms might be used, the particularone embodying said screw isillustrated.

A hand control means is provided for operating lever 21 andwhile thismight take various forms, in the embodiment of the invention illustratedthe same comprises a shaft 55 which ,will be suitably supported andwhich has secured to its ends hand wheels 4| and 42 havin handle knobs55 and 55 respectively thereon. Shaft 55 carries a beveled gear 45meshing with another beveled gear 55 secured to a shaft 51. Shaft 51will be suitably supported in bearings (not shown) and has secured toits other end a beveled gear 55 which meshes with a beveled gear orpinion 55 secured to one end of a shaft 55. Shaft 55 will be suitablysupported-and has secured to its opposite end a beveled gear 5 I. The

' screw 55 is embraced by a nut 52 shown as of considerable length andas held from longitudinal movement in and journaled in spaced bearings55 illustrated as of the ball bearing type.

Nut 52 has secured thereto or formed thereon a beveled gear 52a withwhich beveled gear 5| meshes. The screw 55 extends through the nut 52and has secured to its lower end a splined.

head 55. Head 55 is disposed in and splined in, so as to belongitudinally movable in, the hub 55a of a beveled gear 55. Beveledgear 55 or its hub 55a is journaled in spaced bearings 55 also shown asof the ball bearing type. A sleeve 51 is'shown surrounding hub 5511between bearings .55. Gear 55 is also held from longitudinal movement inbearings 55. A beveled pinion 55 meshes with gear 55 and is connected toa shaft 55 which is connected to the driven shaft 55 of a hydraulicmotor 5|. Shaft 55 may have secured thereto a pinion 52 meshing witha-gear 55 carried on a shaft 55. Gear 55 is therefore driven by motor 5|and can be connected to any other member which is to be driven. Aconduit 55 extends from pump |5to motor 5| through which the fluid forable in gear hub 55a. screw 55 .to move the same in nut 52 in a direc- 4driving motor 5| will pass. Motor 5| will also be provided with adischarge conduit 55 extending from the motor back to the pump I5.

Assuming the pump I5 and the auxiliary pump l9 are being driven and itis desired to drive gears 52 and 55 and the member connected thereto,such as a gun turret on a warship, the operator will turn one or both ofthe hand wheels II and 52. This will turn shaft 51 and shaft 55 will beturned through gears and 45, thus rotating nut 52 through gears 5| and52a. Screw will be moved as will be member 55. Lever 21 will be movedand assuming that screw 55 moves upward link 25 and valve II will bevery slightly raised. In practice an exceedingly small movement of valveI1 is sufficient to permit enough oil to pass therethrough to operatepiston I2. When valve I1 is thus moved upwardly the port communicatingwith conduit I5 is uncovered and fluid or oil can pass into cylinder l5between lands Fla and "b and through conduit |5 to the right hand end ofcylinder l5. Piston I2 will be moved to the left by this fluid or oil.Any fluid in the cylinder |5 at the left hand end of piston |2 will bedischarged through conduit it into cylinder |5 between lands lla and Heand will pass out through conduit 25 to a suitable storage tank. Whenpiston |2 is moved to the left the tflting plate or box |5a is movedabout its trunnion lie, the stroke of the pump is changed from neutraland liquid is delivered by pump ID to the motor 5|. When tilting plateIlla was moved segment 52 was moved by trunnion ||Ie and cam 25 wasrotated in a counterclockwise direction. The cam groove 254 at onceacted .upon the roller therein carried on stud 25 and lever 21 was againmoved downwardly and valve I! moved toward its central position. Inpractice valve ll varies but slightly from central position and asstated when it is moved upwardly slightly from-this position by screw 55being operated from the hand control means cam 29 immediately depressesthe left hand end of lever 21 to bring the valve back to centralposition. As soon as tilting plate Ila is moved the pump operates andmotor 5| is driven, turning gears 52 and 55 and rotating the turret. Theturret is very quickly moved and the operator will stop or retard theoperation of the hand control meanswhen the turret approaches thedesired position. When motor 5| operates shaft 55 and gear 58 arerotated, thus rotatin'g gear 55. This rotates the head 55, which asstated, is splined to gear 55 and is longitudinally mov- Head 55 'thusrotates tion opposite that in which it is moved by the rotation of nut52 as above set forth. The movement of head 55 isthus a differentialbetween the movements or effects of nut 52 and gear 55. If the operatorceases to operate the hand wheels 4| and 52 or if the effect of gear 55on screw 55 is greater than the effect of nut 52 screw 55 and head 55are moved downwardly. Motor 5| is therefore tending to move piston valveII to control piston l2 to change the stroke of the pump back toneutral. As soon as head 55 becomes stationary due to the rotation ofgear 55 and the differential action between .gear 55 and nut 52, valveII has been moved to central position. As the motor through gear 55continues to move head 55, valve I! will be, moved slightly below itscentral position and fluid will pass from conof piston l2. This willmove piston'l2 to the right and tilting plate Ifla will be moved tobring the stroke of the pump back to neutral. 'As this occurs, motor Blwill decrease in speedand the tendency to move head 35 and the righthand end of lever 21 downwardly will decrease progressively. Whentilting plate Illa is thus swu toward its neutral position segment 32 isrotated as is cam 29 and cam slot 29a raises the left hand end of lever21 to bring valve l1 back to central position. The action continues withmotor 6| tending to move head 35 downwardly and. valve 11 downwardly andwith cam 29 lifting the left hand end of lever 21 to liftvalve l1 andbring it to central position. These movements of said parts continueuntil motor 6| is stopped, tilting plate Illa is in neutral position andvalve I1 is in central position. As stated the movement. of valve Ilisvery slight. It will be noted that the. connection of lever 21 to thestroke changing mechanism through cam 29 is I such as to give anon-linear movement. In other wordslever 21 and valve 11 are moved bycam 29 in a non-direct ratio to the change of stroke. This is animportant feature. The cam can be designed to bring the valve II tocentral position more quicklythan it would be so brought with aconnection between lever 21 and the segment 32 giving a linearmovement.. The parts are thus brought to the desired position and theturret is stopped at the desired point with the deceeration at zerowithout the mechanism overrunning or "hunting for the final position. Totake a specific example, assumin that there was a connection betweenlever 21 and cam 29 giving a linear movement or a. connection giving adirect or constant ratio of movement between lever 21 and cam 29 andthat tilting plate Illa is in position for 10 percent of full stroke,the motor would then be running at 10 percent of full speed and lever 21would be at 10 percent displacement. It would be necessary for the motorto make a certain number of revolutions to act sufliciently on head 95to move lever 21 so that valve l1 would be brought to central position.With a connection giving a non-linear movement or in other words amovement varying from a linear movement and having a variablerationbetween. the movement of lever 21 and cam 29 as disclosed and the strokeat 10 percent and the motor running at 10 percent of its full speed thecam could be designed so that it would at the same time be only 2percent from the position causing valve l1 to take its central position.The pump thus need only make Vs of the number of revolutions that woulda be necessary with a connection giving a linear movement. The cam canbe designed to give the desired action on the valve according to-- thegear ratio of gears 59 and 55. The number of revolutions that the motorcan make from full speed to stop is usually limited in thespeciflcations or the number of degrees that the turret shall move fromfull speed to stop is specified. Again if a turret to be turned by agear 63 is to be driven at a maximum speed of 10 degrees per second. andthe maximum value of acceleration is set at 10 degrees per second persecond, then the shortest possible time in which the turret could bestopped from full speed is one second, assuming the acceleration wereperfectly linear. The distance the turret would travel during this onesecond of time would then be 5 degrees. Thus. if the hand wheels arebeing rotated at the equivalent of top speed of the turret and thensuddenly stopped. the turret would travel a minimum of 5 degrees beforestopping. Therefore, at top speed a turret must lag behind the handwheel position by '5 degrees, otherwise the turret would over travel itstrue corresponding position which is undesirable. If this velocity lagis linear then at half speed the velocity lag would be 2.5 degrees,

and at 151- speed 0.5 degrees, etc. The effective gear ratio between theturret and the'pump" stroke adjusting means must be such that ,5 degrees-.(or more) rotation of the turret is required to reduce the pump strokefrom its maximum value to zero.

the above example when the hand wheels are suddenly moved the equivalentof one degree rotation of the turret, the maximum pump stroke instead ofbeing /5 of a full stroke would beincreased for example,'to yr of fullstroke,'"and similarly the maximum velocity of theturret, assuminginstantaneous acceleration, would be 2 of the full velocity. It isimmediately apparent therefore, that with a suitably contoured cam-thetime required for the turret to reach its new position one degree fromits original position is materially reduced and the objection ableresponse time lag has been appreciably diminished. While theoreticallyit might appear that when the hand control means is first operated thescrew 36 would be elevated and the r ght hand end of lever 21considerably-elevated, in practice this does not take place ascam 29immediately acts to depress the left hand end of lever 21. Lever 21 hasconsiderable.. m ove-- ment but it really in efiect pivots about itsconnection to link 26.

If'the hand wheels 4| and 42 were rotated to move screw 36 downwardly,the action will be exactly the same as already described exceptthatmotor 6| would be driven in the opposite direction and the turret wouldbe turned in the opposite direction from that above described. From theabove description it willbe seen that I have provided a simple andeflicient control mechanism for a hydraulic system or assembly. Veryaccurate control can be had over the driven parts which can be quicklymoved and themceleration and stopping of the parts performed as desired.Broadly the invention contemplates a connection giving a non-linearmovement or movement which varies from a linear move ment between thedifi'erentially moved member 35 and the stroke changing mechanism. Thestructure illustrated and described is merely oneembodiment of theinvention. The device has been amply demonstrated in actual practice andfound to be very successful and emcient.

It will, of course, be understood that various changes may be made inthe form, details, ar-" rangement and proportions of the parts, withoutdeparting from the scope of applicants invention, which generallystated, consists in a -d vice capable of carrying out the objects aboveset forth, in the parts and combinations of parts disclosed and definedin the appended claims. I What is claimed is:

l. A control device having in combination, a

hydraulic motor. a variable stroke pump sup 7 plying liquid to and fordriving said motor, fluidoperated means for varying the stroke of saidpump, a fluid control valve for controlling said means, a leverconnected intermediate its ends to said valve, a hand control meansconnected to one end of said lever for moving said end, said lever beingalso connected at said latter end to said motor to be moved by operationof said motor in a direction opposite to that in which it is moved bysaid hand control means, and a connection between said first mentionedmeans and the other end of said lever for movins said other end with amovement which varies from a linear movement whereby said valve is givena movement which varies from a linear movement.

2. The structure set forth in claim 1, said last mentioned connectioncomprising an osciilatable operated means for moving an element of saidpump for changing the stroke of said pump, a

valve for controlling said means, a lever for actuating said valve andconnected thereto, a member connected to one end of said lever, amanually-operated means for moving said member in one direction, meansdriven from said motor for moving said member in the opposite direction,and a connection between said lever and element for moving the portionof said lever connected to said valve with a movement which varies froma linear movement,

4. A- control device having in combination, a hydraulic motor, avariable volume delivery pump for supplying liquid to and for drivingsaid motor, fluid-operated means for moving an element of said pump forchanging the volume delivered thereby, a fluid control valve forcontrolling said first mentioned means, a member connected to said valvefor actuating the same, a manually-operated means for moving saidmember, a differential mechanism connected to said manually-operatedmeans and said mem-- ber and also connected to said motor, and a cammoved by said first mentioned means and connected to said member formoving the portion of the latter connected to said valve with a movementwhich varies from a. linear movement, whereby said valve is moved with amovement varying from a linear movement.

5. The structure set forth in claim 4, a second member moved in directratio to the movement of said element and means for moving said cam bysaid second member.

6. A control device having in combination, a hydraulic motor, a variabledelivery pump for supplying liquid to and for driving sa d motor, fluidoperated means for changing the delivery of said pump, a cylinder, apiston in said cylinder for actuating said means, a valve forcontrolling movement of said piston, a lever pivotally connectedintermediate its ends to said valve, a member connected to one end'ofsaid lever, a manually operated means for moving said member in onedirection to cause movement of said valve and means, means driven ,fromsaid motor connectcd to said member for moving it in the oppositedirection, a member moved in direct ratio to said first mentioned 8.means and a cam driven by said last mentioned member and connected tothe other end of said lever for moving the portion of said'leverconnected to said valve with a non-linear movement and thus move saidvalve with a non-linear movement.

7. A control device for a movable object having in combination, ahydraulic motor for causing movement of said object, a variable strokepump for supplying liquid to and for driving said motor, fluid operatedmeans for varying the stroke of said pump to vary the volume of liquidsupplied to said motor, a valve for controlling said means, a handcontrol means, a lever, a connection between said hand control means andsaid lever, a second connection between said lever and valve, 9. thirdconnection between said lever and said motor for moving said lever whensaid motor is operating, and a fourth connection between said lever andsaid first mentioned means for moving said lever and said secondconnection with a;movement which varies from a linear movement, wherebysaid valve is moved with a movement which varies from a linear movementto bring said valve to neutral position with said object in the desiredposition.

8. The structure set forth in claim 7, said first mentioned connectionbeing at one end of said lever, said last mentioned connection being atthe other end of said lever and said second connection being a pivotalconnection disposed intermediate the ends of said lever.

9. A control device having in combination, a fluid-operated motor, avariable volume delivery pump for supplying liquid to and for drivingsaid motor, a fluid-operated means for varying the volume delivered bysaid pump, a fiuid control valve for controlling said means, a memberconnected to said valve for moving the same, a hand control means, adifierentially acting means connected to said member and also connectedto said hand control means to be moved in one direction thereby, saiddifierentiallyacting means also being connected to said motor andmovable by operation thereof in a direction opposite to that in which itis moved by said hand control means, and a connection between said firstmentioned means and said member for moving the portionof the latterconnected to said valve with a movement varying from a linear movement.

Gaiwm A. KANE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

